Oedematous corneal response of the fellow control eye to lotrafilcon a and vifilcon a hydrogel contact lenses in the rabbit.

PURPOSE: To compare central corneal swelling after 24 h in eyes wearing Lotrafilcon A (high Dk silicone hydrogel) and Vifilcon A (low Dk hydrogel) lenses and the fellow control eyes of rabbits.

METHODS

24 New Zealand albino rabbits, free of corneal and conjunctival disease, were anaesthetised with ketamine and xylazin. In 12 rabbits, the right eye was fit with the high Dk Lotrafilcon A silicone hydrogel lens. In the other 12 rabbits, the right eye was fit with the low Dk Vifilcon A hydrogel lens, whereas the left eyes were kept as control eyes. Thereafter, the lens-fitted eyes had partial tarsorrhaphy that left a central gap of approximately 4 mm in length. After 24 h the eyelids were opened and the lenses removed. Central corneal thickness was measured using an ultrasonic pachymeter (Mentor O&O-Advent).

RESULTS

Central corneal oedema induced by Vifilcon A lens was significantly higher than that with the Lotrafilcon A lens (p < 0.0001). The oedema of the fellow eyes paired with the Vifilcon A lens-wearing eyes was also higher than that of the fellow eyes paired with the Lotrafilcon A lens-wearing eyes (p < 0.01).

CONCLUSIONS

The Lotrafilcon A lens induced significantly less corneal oedema than the Vifilcon A lens. Corneal oedema of the fellow eyes appears to be influenced by the swelling of the contralateral lens-wearing eyes. The oedema of the fellow control eye was significantly lower when there was less oedema in the contralateral eye wearing a high Dk silicone hydrogel lens. This may be a sympathetic physiological response. The presence of silicone in the high Dk hydrogel lens may suppress corneal oedema in the lens-wearing eye, thus affecting the fellow eye.